In MExLab developed program LightsComputation® to calculate the position of Earth and Sun for an observer on the surface of a celestial body, taking into account the relief, forming a particular configuration of horizontal line. This program was designed for visual analysis of proposed sites for the lunar landing research stations missions Luna-glob and Luna-Resurs (Fig. 3). Namely, at certain time intervals to obtain the position of the Sun above the horizon, which is important for supplying energy solar batteries providing operation of scientific equipment, and the visibility of the Land necessary for the transfer scientific and research information on the tracking station for further processing. Figure 1 shows an example of the correctness of the calculation of the visible horizon formed by the topography of the surrounding area. Example of calculation of illuminance on the area 75.54 N, 8.07 E is presented in figure 2.
Fig. 1. An example of visible horizon comparison at the Apollo 15 SPACECRAFT landing site with horizon modeled in the program LightsComputation®
Fig.2. The LightsComputation® working window calculation of illuminance on a site 75.54 N, 8.07 E. the table provides data on 01.10.2015 30.10.2015 about horizontal coordinates of the Sun and Earth visible from the moon's surface. On the chart shown by the black solid line terrain visible horizon, the blue solid line is the Earth track, the red solid line is the Sun track in horizontal coordinates.
Fig. 3. The result of the calculation in the program LightsComputation® light for one of the intended points of (lat: 75.6°, long: 8.4°) of landing space vehicle Luna-glob in the Northern circumpolar region for the period from December 29, 2015 January 29, 2016. The black line denotes the apparent horizon at this point, the red corresponds to the movement of the Sun during this period, and blue shows the appearance of the Earth.